Apparatus for providing an oxygen containing atmosphere



y 1969 J. w. THOMAS ETAL 3,445,194

APPARATUS FOR PROVIDING AN OXYGEN CONTAINING ATMOSPHERE Sheet Filed Nov.5, 1965 May 20,1969 J w THOMAS ETAL 3,445,194

APPARATUS FOR PROVIDING AN OXYGEN CONTAINING ATMOSPHERE Filed Nov. 5,196:5 Sheet ,8 of e May 20, 1969 J w THOMAS ETAL 3,445,194

APPARATUS FOR PROVIDING AN OXYGEN CONTAINING ATMOSPHERE Sheet Filed Nov.5, 1963 NN QN gm. o fmw May 20, 1969 J. w. THOMAS ETAL 3,445,194

APPARATUS FOR PROVIDING AN OXYGEN CONTAINING ATMOSPHERE Filed Nov. 5,1963 Sheet 4 of 6 4 7 E qr-O xmn- P3 159) g 2 162 Q ar-J-r QLOWER M02 12Q7 f 8Q 61 99 55 67 VALVE MT 142 141 457 OTORS y 1969 J. w. THOMAS ETAL3,445,194

APPARATUS FOR PROVIDING AN OXYGEN CONTAINING ATMOSPHERE Filed Nov. 5,1963 Sheet 5 of 6 May 20, 1969 J, w TH ET AL 3,445,194

APPARATUS FOR PROVIDING AN OXYGEN CONTAINING ATMOSPHERE Sheet Filed Nov.5, 1963 m N M I m I M ENV E mso m I C T R E m? G A R N 5 0 W E 7 H 2 0W60 5 BY- PAss TIME -M|N.

United States Patent 3,445,194 APPARATUS FOR PROVIDING AN OXYGENCONTAINING ATMOSPHERE Jess W. Thomas, New York, N.Y., Joshua R. C.Brown, Chesterton, Ind., and James J. Anderson, Stevensville, Mich.,assignors to Whirlpool Corporation, a corporation of Delaware Filed Nov.5, 1963, Ser. No. 321,626

Int. Cl. B013 7/00; A23b 1/00; B01d 53/02 U.S. Cl. 23-281 ClaimsABSTRACT OF THE DISCLOSURE An atmosphere generating system having acatalytic burner adsorption apparatus, an air source and fluid circuitryfor providing and maintaining a food preserving atmosphere in a foodstorage container by flowing air through the adsorption apparatus, thenflowing atmosphere through the adsorption apparatus to a place ofdisposal for a first predetermined time period, then flowing atmospheredirectly to the storage container for a second predetermined timeperiod, and then flowing atmosphere through said adsorption apparatus tothe storage chamber to transfer the remainder of air to the containerand provide a substantially hydrocarbon free atmosphere to the containerfor a third predetermined time period.

Summary of the invention This invention relates to an apparatus forproducing and maintaining an atmosphere in a receiver having preselectedcontrolled amounts of oxygen and carbon dioxide.

One of the features of this invention is to provide an improvedapparatus for producing and maintaining an atmosphere having preselectedcontrolled amounts of oxygen and carbon dioxide for a receiver such as astorage chamber in which animal and vegetable materials may be stored.

Another feature of the invention is to provide an improved generator inthe form of a catalytic burner and associated parts thereof forgenerating such an atmosphere by the combustion of a hydrocarbon fuel inthe presence of excess air.

Another feature of the invention is to provide an improved automaticcontrol apparatus as a part of the generating apparatus for providingautomatic operation under the desired controlled conditions and in whichthese conditions can be altered as desired.

Other features and advantages of the invention will be apparent from thefollowing description thereof, particularly as illustrated in theembodiments shown in the accompanying drawings. Of the drawings:

FIGURE 1 is a semi-diagrammatic view showing the relationship of theparts of this embodiment of the atmosphere producing apparatus.

FIGURE 2 is a fragmentary plan view of one of the absorbers forming apart of the apparatus of FIGURE '1.

FIGURE 3 is a sectional view taken substantially along line 3-3 ofFIGURE 2.

FIGURE 4 is a fragmentary detail sectional view of a portion of theapparatus of FIGURE 3.

FIGURE 5 is a fragmentary side elevational view partially in section ofa catalytic burner forming a part of the apparatus of this invention.

FIGURE 6 is a sectional elevational view taken substantially along line66 of FIGURE 5.

FIGURE 7 is a schematic Wiring diagram of the electrical circuit portionof the apparatus showing the parts of the automatic control.

FIGURE 8 is an enlarged detail of a portion of the electrical circuit ofFIGURE 7.

3,445,194 Patented May 20, 1969 FIGURE 9 is a graph illustrating how theoperating conditions may be changed with a typical burner to producedesired amounts of carbon dioxide and oxygen.

FIGURE 10 is an enlarged detail cross section of FIG URE 3.

In Bedrosian et al. Patent 3,102,777, assigned to the same assignee asthe present application, there is disclosed and claimed an apparatus andmethod for providing an atmosphere with controlled amounts of oxygen andcarbon dioxide which may be used to provide a storage atmosphere in areceiver, such as a storage chamber, for the preservation of animal andvegetable materials. In the copending Lannert et al. application Ser.No. 213,- 398, filed July 30, 1962, now Patent 3,205,049, also assignedto the same assignee, there is disclosed and claimed one form of anapparatus for producing such an atmosphere.

The present invention is a further development in this field andutilizes a catalytic burner generator with a pair of activated carbonadsorbers with one being used to adsorb undesirable gases such asethylene and controlled amounts of carbon dioxide while the other isbeing regenerated by removing the adsorbed undesirable gases and carbondioxide. The apparatus of this invention also utilizes a pair ofvariable timers with one being used to control the amount of oxygenprovided to the receiver or storage chamber and the other regulating theamount of carbon dioxide provided to the receiver with both timers beingreadily adjustable so as to vary the amount of these two gases.

The system As shown in FIGURE 1 there is provided a catalytic burner 10that is supplied with a hydrocarbon fuel gas by way of a line 11 andpressurized air by means of a line 12 from a blower 13. The gas from theline 11 and air from the line 12 mix in the line 12 just before itenters the burner with the flow of gas being controlled by means of anadjustable orifice 14. In the air line 12 there is provided an airregulating valve 15 and a fixed orifice 14a while in the gas line 11there is provided a gas regulator 16 that is connected by way of a line17 to the air line 12. Attached to the gas regulator line 17 is amanually reset flash-back pressure switch 18- which is normally closedbut which opens if there is flash-back in the burner 10 in order to shutoff the system in a manner to be described hereinafter.

The gas regulator line 17 also contains an air pressure switch 19 whichis normally open when the system is not operating but which is closed byair pressure when the amount of air provided by blower 13 is suflicientto support combustion of the burner 10. This prevents the systemoperating when there is insufiicient air pressure.

The gas and air mixture enters the burner 10 at the intake manifold 20on the top of the burner and the products of combustion leave throughthe exhaust manifold 21. Located in the intake manifold 20 is a manuallyreset flash-back thermostat 22 above the catalytic portion of the burner10 that is normally closed but is opened by any series of flash-backburning within the manifold 20. This thermostat switch 22 is an addedsafety device functioning in combination with the more remote flash-backpressure switch 18.

Ignition of the gases within the burner 10 is accomplished by means of aspark plug 23 in the exhaust manifold 21. This exhaust manifold isprovided with a flame detection switch 24 which detects burning andcloses the electrical circuit to the controls to be describedhereinafter for proper operation of the apparatus.

The products of combustion from the burner 10 containing oxygen, carbondioxide and inert gases from the air flow through an exhaust line 25 toa water cooled condenser 26 where condensible vapors are removed fromthe exhaust. The condenser contains a flame arrester 27 to prevent anyburning past this point within the generator.

For cooling purposes there is provided a water inlet line 28 leading tothe top plenum 29 and then to coils (not shown) within the condenser 26.From here the water flows through a line 30 to the top of the burner 10.Water flows through this top of the burner from one portion to anotherthrough a jumper tube 31 and from the top of the burner to the bottomthereof through a jumper water line 32. Water flows through this bottomof the burner 10 by way of another jumper line 33 and flows from theburner by way of an outlet line 34. The details of construction of theburner and its parts including the cooling water lines are presentedlater.

In the exhaust water line 34 there is provided a strainer 35 forstraining out any solid particles and from here the outlet water flowsthrough a chamber 36 in which is contained a sensing bulb 37 for amodulating water valve 38. A water line 39 is provided leading from thechamber 36 by way of a fiow control valve 40. With this arrangement flowof exhaust water from the burner 10 is controlled by the temperature ofthe water in the manner explained in the above-mentioned copendingapplication Ser. No. 213,398. From this control apparatus the waterexhausts through an exhaust line 41.

Condensate from the condenser 26 flows from the condenser by way of alower plenum 42 and a condensate disposal line 43.

From the condenser 26 a gas conduit 44 leads to a valve 45 having adamper 46 therein operated by a motor 47. From this valve 45 a conduit48 leads to a conduit 49 which exhausts to atmosphere.

From the valve 45 a conduit 50 leads to a valve 51 having a damper 52whose operation is controlled by a motor 53. From this valve 51 aconduit 54 leads to a conduit 55, one end of which leads to a valve 56and the other end leads to a valve 57. The valve 56 has a damper 58operated by a motor 59 while the valve 57 has a similar damper 60operated by a motor 61.

Also leading from the valve '51 is a conduit 62 intersecting a conduit63 which intersects at one end a conduit 64 and connects at the otherend to a valve 65. This valve like the others has a damper 66 operatedby a motor 67.

The valve communicates by way of a conduit 68 with a storage chamberidentified diagrammatically in FIGURE 1 at 69. The valve 65 alsocommunicates by way of the conduit 70 with the previously mentionedconduit 49.

Valve 56 is located at the bottom of adsorber 70 which is one of a pairof adsorbers with the other being identified at 71. Valve 56communicates with the bottom of the adsorber 70 through a conduit 72while valve 57 is provided with a similar conduit 73. Valve 56 alsocommunicates by way of a conduit 74 with the exhaust conduit 49.

At the top of the adsorber 70 there is provided a valve 75 having adamper 76 operated by a motor 77. One side of this valve communicateswith the previously mentioned conduit 64 while the second sidecommunicates with a conduit 78 which is part of an air line leading froma second blower 79. Both blowers 13 and 7-9 are operated by a commonmotor 80 and a conduit 81 leads from blower 79 to a valve 82 having adamper '83 operated by a motor 84.

Located between the blower 79 and the valve 82 is a normally open airpressure pulse switch 85 adapted to be momentarily closed by pressurepulses in the conduit 81.

The valve 82 communicates with conduit 78 and also with a valve 86 atthe top of adsorber 71 by way of a conduit '87. The valve 86 is providedwith a damper 88 operated by a motor 89. Valve 86 communicates with thetop of adsorber 71 through a conduit 90 and corresponding valve 75 isprovided with a similar conduit 91.

Also in the system of FIGURE 1 as well as certain other figures there isa gas valve 92 in the gas line 11 operated by a solenoid 93. There arealso control thermostats and switches including a fuel pressure switch94 that is normally open when the system is not in operation but whichis closed by the fuel pressure when the fuel supply is adequate for theproper operation of the system. This fuel pressure switch is illustratedin the circuit Wiring diagram of FIGURE 7. There is also provided acooling water thermostat 95 in the cooling water exit line 34 which isnormally closed but which opens to break the electric circuit, as shownin FIGURE 7, if the cooling water is excessively hot which wouldindicate improper operation of the burner, or inadequate water supply.

The burner 10 is provided with an operation sensor 96 immediately abovethe burner which is normally open when the system is not operating butwhich is closed by the heat of the burner when the system is operatingnormally. In the electrical circuit, as shown in FIGURE 7, there isprovided an ignition switch 97 which is normally closed whether or notthe system is operating and is open only for interrupting the electricalcircuit when such is desired as for servicing various parts thereof.

The dampers of all the valves in FIGURE 1 are shown in theirde-energized (spring loaded) solid line positions. When the respectiveelectric motor for each damper is energized, that damper then moves tothe dotted line position, also shown in FIGURE 1. The electrical circuittimers and other operating controls for these various valves aredescribed in detail hereinafter.

The generator The catalytic burner or generator 10 is shown in detail inFIGURES 5 and 6. The burner comprises an enclosing frame 98 that isgenerally rectangular and arranged horizontally. This frame has a spacedtop 99 and bottom 100 that are substantially parallel to each other. Thebottom 100 is provided with upwardly extending spaced brackets 101 of Lshape having coplanar tops. Certain of these brackets are shown in endelevation in FIGURE 6 and in side elevation in FIGURE 5. In FIGURE 5only two of the brackets are shown, it being understood that otherbrackets (in the preferred embodiment some 40 in number) are providedspaced apart along the entire bottom 100.

The tops of the brackets support parallel rod members 102 that are ofsquare cross section, as shown in FIG- URE 5, and these in turn supportspaced parallel second rod members 103 that are at substantially rightangles to the rod members 102. The first rod members 102 are square sothat they will not roll under the forces of heating and cooling withinthe burner.

Supported on the assembly of rod members 102 and and 103 is a perforatedsupporting screen 104 of the type shown and described in R. I. Ranumcopending application Ser. No. 213,397, filed July 30, 1962, now Patent3,203,770, also assigned to the same assignee as the presentapplication.

The screen 104 is provided with parallel strengthening ribs 105. Thescreen is loosely attached to the rod members 102 by spaced loose Wireties 106.

The screen 104 supports a granular catalytic bed 107 which isillustrated, broken away, in FIGURE 5. This bed 107 is as described inthe above-mentioned Ranum application and is a well known material forproviding low temperature burning of fuel in the presence of the fuel inthe presence of the oxygen in the air.

The burner 10 is provided with a top plate 99 as previously mentionedthat is spaced from the top of the bed 107 to provide an upper space108. The burner is also provided with the above-described bottom plate100 spaced from the bottom of the bed as defined by the screen 104 toprovide a bottom space 109.

The intake manifold 20 to the burner communicates with the top of thespace 108 by means of an air-gas distributor channel 110 mounted on thebottom surface of the top plate 99 to receive gas and air mixture fromthe manifold 20. The sides of this channel 110 are provided withoutwardly extending openings 111 that are closely spaced along thelength of the channel which extends the full length of the burner frame98. These small openings are spaced about a quarter of an inch apart andproject jets of gas and air mixture laterally above the catalyst bed107. The bottom manifold 21 contains the spark plug 23 which initiatesthe burning.

In order to cool the burner in the manner and for the purposes disclosedin the above-mentioned Ranum application there is provided a waterjacket plate 112 on the outer surface of the top plate 99 havingparallel adjacent water passages 113 therein. The bottom plate 100 isprovided with a similar water jacket plate 114 provided with waterpassages 115 therein. The passages 113 on one side of the manifold arearranged in series flow relationship and the passages 113 on the otherside of the manifold are similarly arranged in series flow. In the lowerwater jacket 114 the passages 115 on opposite sides of the manifold 21are arranged in the same manner.

The various sets of passages are connected in series by the previouslydescribed jumper line 31, jumper line 32 and jumper line 33 for waterflow through these passages in series. The water enters through afitting 116 which is attached to water line (FIGURE 1). The water leavesthrough fitting 117 which is attached to water outlet line 34 (FIGURE1).

The manual reset flash-back thermostat 22 is located on the outside ofintake manifold 20 at one side thereof while the operation sensor 96 isalso located on the outside of the intake manifold on the opposite sidethereof. The flame detection switch 24 that was previously described islocated in the outlet manifold 21 at one end thereof.

In order to reduce heat loss from the burner 10 including that partsurrounding the sides of the bed 107 and the sides of the top space 108and bottom space 109, there is provided temperature resistant insulation118, as shown in FIGURES 5 and 6.

The adsorbers Each of the adsorbers 70 and 71 is identical in structureand so only adsorber 70 will be described in detail as representative ofthe two. The adsorber is illustrated most clearly in FIGURES 2 and 3.The adsorber 70 is illustrated without the finely divided activatedcarbon which is the adsorbing medium, as described in Brown et al.copending application Ser. No. 213,520, filed July 30, 1962, now Patent3,203,771 also assigned to the same assignee.

The adsorber has a cylindrical shell 119 of sheet metal and the likewith permanently attached metal bottom 120. Above this bottom there isan inwardly extending annular groove 121 on which is held the support122 for the bed of activated carbon (not shown). This support comprisesan expanded metal grating 123 on which is positioned a metal screen 124.Edge reinforcements 125 are provided and the whole is retained in theassembly by an enclosing rubber channel 126. It is the channel whichcontacts the top surface of the metal forming the groove 121.

The shell 119 is provided with a removable cover 127 of sheet metal onwhich is located the top valve 75. The bottom valve 56 is mounted on thebottom closure 120. The top cover 127 is releasably sealed to the top ofthe cylindrical shell 119 by a rubber basket 128 held in an inverted rimchannel 129 on the cover 127 and bearing against an edge bead 130 at thetop of the shell 119. A split ring 223 having tapered surfaces 224 and225 forces the inverted rim channel 129 of top cover 127, rubber gasket128 and edge bead 130 into sealing engagement when the handle 226 oftoggle clamp 227 is positioned as shown in FIGURE 2.

Beneath the removable cover 127 there is provided a removablecylindrical retainer 131 that is relatively shallow and that supports acircular screen 132 similar to the bottom screen 124. The bottom plateis spaced from the bottom support 122 to provide a manifold space 133.The retaining screen 132 at the top is similarly spaced from the cover127 to provide a manifold space 134. As mentioned previously the cover127 is removable by merely lifting up after ring 223 is removed. Thescreen retainer 131 is similarly removable as it is loosely positionedin the void between the cover 127 and the activated carbon (not shown).

In order to operate the upper damper 76 there is provided at one sidethe motor 77. This motor operates a shaft 135 by way of a geartransmission 136 and a clutch arrangement 137. A spring 138 is providedto urge the damper 76 toward its normal solid line position as shown inFIGURE 1.

The bottom valve 56 is provided with a similar motor 59 and operatinggear transmission, clutch and spring.

The electrical control circuit The control circuit for the embodiment ofthe invention disclosed in the drawings is shown in FIGURE 7 with thetimers and adjacent portions of the circuit shown in FIGURE 8.

The apparatus is supplied with power from two electric leads 139 and140. A customary fuse 141 is provided as Well as a double pole masterline switch 142.

From one side of the switch 142 there is provided an electric line 143to a relay 144. This relay is provided with a double pole double throwswitch 145 having two poles 146 and 147 and four contacts 148, 149, 150and 151. The two poles 146 and 147 are connected by a lead 152.

From the line 143 a line 153 is connected to an ignition control 154.This is a conventional ignition control system commonly used with oil orgas burners and is a readily available commercial unit. The controlfunctions to connect terminal 1 to terminals 3 and 4, as indicated bythe dotted lines on FIGURE 7, for a predetermined period of time thatmay be set on the control 154. Upon the expiration of this predeterminedor preselected time, terminal 1 will automatically be disconnected fromterminals 3 and 4 unless the flame detector switch 24 has closed toindicate the presence of flame in the burner. If the flame switch 24closes before the expiration of the predetermined time, terminal 1 willbe disconnected from terminal 4 but remains connected to terminal 3.

In line 153 are the various switches previously described which are usedto insure that the apparatus of this invention is functioning properly.Thus, these switches which are connected in series include the airpressure switch 19 which closes when there is a proper amount of air forefiicient combustion, ignition switch 97 which is normally closed at alltimes and is customarily only opened when it is desired to remove thecontrol 154 from the circuit as for servicing or the like. Otherswitches in this series are the flash-back pressure switch 18 which is asafety switch and which is normally closed unless there has been aflash-back of flame in the burner, the manually reset flash-backthermostat 22 which is normally closed and located on the intakemanifold monitors high temperatures caused by flash-back burning withinmanifold 20, and a fuel pressure switch 94 that is normally open but isclosed when the gas in the system is at sufiicient pressure forefiicient burning. Finally in this series of switches is the coolingwater thermostat switch 95 which is normally closed but opens if thecooling water from the burner 10 is excessively hot. The location ofthese various switches in the system are shown in the other views andhave been described.

Typical operating conditions for the apparatus of this invention involvecombustion within the burner 10 at a temperature below about 2000" F. inorder to prevent formation of harmful oxides of nitrogen. The powersupply is a conventional 115 volt 60 cycle alternating current supplyand the settings for the various thermostats and pressure switches inone embodiment may be as follows: The safety thermostat 173, normallyclosed, is set to open at 145 F. the cooling water thermostat 95,normally closed, is set to open at 190 F., the air pressure switch 19 isarranged to close at a pressure of about 2.5 inches of water, theflash-back pressure switch 18 is set to open at a pressure of about 5.7inches of water, the fuel pressure switch 94 closes at a pressure ofabout 4.0 inches of water, the flash-back thermostat 22 is normallyclosed but opens at about 325 P. which has been found sutlicient to showexcessive flash-back, the operation sensor 96 closes at about 175 F. andthe flame detection switch 24 which is normally open closes when thetemperature of the gases in the exhaust manifold 21 are about 375 F.These values, of course, are only given for one embodiment of theinvention and may be varied.

Terminal 4 on the control 154 is connected to a transformer 155 whichoperates the spark plug igniter 23. The other side of the transformer155 is connected by a line 156 to a line 157 which is in turn connectedto the second pole 158 of the switch 142.

Terminal 3 of control 154 is connected by line 159 to the operationsensor thermostat 96 previously described. Between line 159 and line 156is connected the solenoid 93 for the gas valve 92, both previouslydescribed.

The other side of the operation sensor 96 is connected to an operatingsolenoid 160 for the relay switch 145 with the mechanical connection ofthe solenoid 160 to the switch poles 146 and 147 being indicated by thedotted line 161.

The other side of the solenoid 160 is connected by line 162 to line 156and also to terminal 2 of control 154.

Terminal 148 of the four terminals on the relay 144 is connected to line163 which is connected to line 164 and to a light 166 whose other sideis connected to the line 156.

Another terminal 149 on the relay 144 is connected by a line 167 to anindicator light 168 whose other side is also connected to the line 156.

The third relay terminal 150 is connected by line 169 to a line 170,while the fourth terminal 151 of the relay is connected by a line 171 tothe motor 47 of a by-pass valve 45.

Between the lines 143 and 156 of opposite sides of the switch 142 thereextends a line 172 in which is located the blower motor 80 for operatingthe two blowers 13 and 79. Also in the line 172 is a manually reset,normally closed, safety thermostat 173 that is located at the gas outletof the condenser 26 that opens to stop the blower 80 if the temperaturein the condenser plenum 29 becomes too great.

The electrical system also includes a cycle timer 174 having anoperating motor 175 that operates a cam 176 to move a switch arm 177between a pair of contacts 178 and 179. One side of the motor 175 isconnected to a line 180 While the other side is connected to the line157. Each of the valve motors 47, 59, 77, 84, 61, 89, 53 and 67 isconnected to this line 157 so that all of these motors are in parallel.

As shown in FIGURE 7 valve motors 59, 77 and 84 are connected to contact178 of the cycle timer while valve motors 61 and 89 are in parallel witheach other and connected to the other timer contact 179. Valve motor 53is connected to line 181 while valve motor 67 is connected to line 182.

The movable switch arm 177 on the cycle timer is connected by thepreviously mentioned line 164 to line 163 from the relay 144.

As is shown in greater detail in "FIGURE 8 the electrical control systemincludes two adjustable timers, one of which is a carbon dioxide timer183 and the other is an oxygen timer 184. These timers are manuallyadjustable to operate for preselected times and are capable of resettingautomatically at the end of the preselected time period. They arecommercially available and are known as Cycl-lFlex timers. The onlydifierence in construction between the two timers is the length of timecycle. Timer 184 has a time cycle which may be varied from 0 to seconds.Timer 183 has a time cycle which may be varied from 0 to 30 minutes.Timer 183 does not utilize the switch (not shown) comparable to switch198 of timer 184.

Timer 184 includes a first energizable means shown as a solenoid 185 anda second energizable means shown as a motor 186. This timer alsoincludes a first electrical circuit 187 extending to a first switch 188with this first switch 188 being connected by way of line to a switch189 in the other or carbon dioxide timer 183. This timer 183 contains afirst energizable means in the form of another solenoid 190 similar tothe solenoid and a second energizable means shown as a motor 191 similarto the motor 186. The timer 183 also contains an electrical circuit 192that is similar to the electrical circuit in the oxygen timer 184.

In addition to the switch 188 the oxygen timer 184 contains a normallyclosed switch 193 with these two switches being operated by the solenoid185 as indicated by the dotted line 194. When solenoid 185 is notenergized the switch 188 is in the open position shown While switch 193engages contact 195. When the solenoid 185 is energized the two switchesare moved down from their solid positions to their dotted line positionsas shown in FIGURE 8 to engage contacts 196 and 197 respectively.

Oxygen timer 184 also contains a switch 198 that is operated by themotor 186 as indicated by the dotted line 199 and a switch 200 that isalso operated by the motor 186 as indicated by the dotted line 201.

Carbon dioxide timer 183 also contains a switch 202 similar to theswitch 193 of the oxygen timer and a switch 203 similar to the switch200 of the oxygen timer. Switches 189 and 202 are operated by thesolenoid as indicated by the dotted line 204 while switch 203 isoperated by the motor 191 as indicated by the dotted line 205 When thesolenoid 190 is de-energized switch 202 engages contact 206 and whensolenoid 190 is energized switch 202 engages contact 207 and switch 189engages contact 208.

As shown at the top of FIGURE 8 switch 202 is connected to line 170while contact 206 is connected to line 180. Contact 207 is connected toline 181 and switch 189 is connected to line 170. Contact 208 is a partof the second circuit 192 and the motor 191 is in its own circuit 209,one side of which is connected to line 157 and the other side of whichis connected to contact 210 of switch 203 and to a line 211.

As is shown in the lower portion of FIGURE 8, the oxygen timer 184switch 193 is connected by line 212 to line 170. Contact is connected toline 182 while contact 197 is connected by line 213 to switch 198. Alsoin timer 184 switch 188 is connected to line 170 by line 214 whilecontact 196 is connected by line 215 to line 187 which in turn isconnected to switch 200. The motor 186 is in its own line 216, one endof which is connected to line 157 by way of a line 217 and the other endof which is connected to a contact 218 of switch 200. Contact 218 isalso connected by lines 219 and 220 to the air pressure pulse switch 85previously described. The line 220 is connected to one contact 221 ofthe swtich 85 and the switch is provided with a movable arm 222 that isnormally out of engagement with contact 221 but which is moved intoengagement by surges of air pressure within the conduit 81 from theblower 79.

Operation With the gas supply through the line 11 and the air supplyfrom the blower 13 both being of sufficient pressure for properoperation of the burner and with all of the precautionary safetyswitches including the air pressure switch 19, ignition switch 97, flashback pressure switch 18, flash-back thermostat 22, gas pressure switch94 and the cooling water temperature thermostat 95 functioning properly,indicating proper operating conditions for the burner, the circuit fromline 143 to terminal 1 of the control 154 will be completed. This causescurrent to flow into the transformer 155 by way of terminals 1 and 4 ofthe control 154 to energize the spark plug 23 and ignite the fuel in thecatalytic burner 10. Current flowing from terminal 3 of the control 154energizes the gas valve solenoid 93 to open the gas valve 92. Currentflowing from line 143 to the double pole double throw relay switch 145and through switch arm 147 to line 167 energizes the indicator light 168to show that the apparatus is functioning. Similarly, current flowingfrom line 143 through pole 146 of the switch energizes valve motor 47 tomove the damper 46 of by-pass valve 45 (fifth valve) to its dotted lineposition as shown in FIGURE 1 so that the initial products of combustionwill pass into line 48 and from there to the ambient atmosphere throughline 49. This is a precautionary measure, as often the initial productsof combustion are contaminated by unburned gases and are thereforevented during this initial period.

As mentioned earlier, the control 154 connects terminal 1 to terminals 3and 4, as illustrated by the dotted lines in FIGURE 7, for apredetermined period of time. Upon the expiration of this predeterminedperiod, which is usually about 70 seconds, terminal 1 will automaticallybe disconnected from terminals 3 and 4 unless flame detector switch 24has closed. If switch 24 closes before the expiration of thepredetermined time interval, terminal 1 is disconnected from terminal 4but remains connected to terminal 3 to keep the gas valve open. Thisautomatic disengagement of terminals 3 and 4, if switch 24 is not closedby flame in the burner, is a safety device in order to shut off both thesparking of the igniter plug 23 and the gas supply as under theseconditions the burner would not be operating properly.

If the burner continues to operate properly, the operation sensor 96closes to energize the solenoid 160 of relay 144 and move the relayswitch poles 147 and 146 out of engagement with contacts 149 and 151 andinto engagement with contacts 148 and 150. This breaks the circuit tothe by-pass valve motor 47 so that the products of combustion are nolonger vented to the atmosphere. The engagement of pole 146 with contact150 energizes the cycle timer motor 175 by Way of switch 202 of thecarbon dioxide timer 183 as shown in FIGURE 8. The electric energy toswitch 202 is supplied by line 169.

The engagement of switch pole 147 with contact 148 operates throughswitch 177 of the cycle timer to energize valve motors 59 (first valve),77 (second valve) and 82 (sixth valve) and moves dampers 58 and 76 totheir dotted line positions which serves to place adsorber 70 in thecircuit from the condenser 26. The energizing ot motor 84 also movesdamper 83 to its dotted line position so that air from the blower 79then flows down through the adsorber 71 by way of line 81, valve 82(sixth valve), line 87 and valve 86 (eighth valve) to rejuvenate theadsorber 71 by removing previously adsorbed carbon dioxide. The air thenflows out the bottom of adsorber 71 and through valve 57 (seventh valve)and line 49 to the ambient atmosphere.

The moving of damper 83 to its dotted line position as described abovecauses a momentary air pulse in line 81 to operate switch 85 and movethe arm 222 into momentary engagement with contact 221 (FIGURE 8).

The engagement of the arm 222 with contact 221 in the impulse switch 85energizes solenoid 185 from power supplied by way of lines 220 and 170and pole 146 of switch 145 which, as described above, is still inengagement with the contact 150. This arrangement means that power issupplied to line 170 from line 143 and connecting line 169.

The momentary closing of switch 222 energizes solenoid 185 and causes itto move switches 188 (first switch) and 193 (fourth switch) of oxygentimer 184 downwardly. This means that switch 188 engages contact 196 andswitch 193 engages contact 197.

Because the bypass valve motor 47 is out of the circuit in the mannerpreviously described combustion products now flow from the condenser 26through line 44, valve 45 (fifth valve), line 50, valve 51 (fourthvalve), line 54 (first conduit), line 55 and open valve 56 (first valve)to the adsorber bed for flow upwardly through the adsorber. The gasesthen flow through the open valve (second valve) into line 64, line 63(second conduit), valve 65 (third valve) and line 70 (third conduit) toexhaust line 49 which exhausts to the atmosphere.

This upward flow of burner gases through adsorber 70 proceeds for apreselected time that was set on the oxygen timer 184. As the adsorber70 had been previously flooded with air in a previous cycle, much asadsorber 71 is now being flooded with air from blower 79 in the mannerpreviously described, by exhausting a portion of the air in adsorber 70to the ambient atmosphere for a preselected time as determined by theoxygen timer 184, all but a predetermined amount of air is removed fromthe adsorber. In other words, the combustion products purge air from theadsorber until the predetermined desired amount remains which will bedetermined by the time set on the oxygen timer 184. At a later stage, tobe described hereinafter, this remaining entrapped air which is ofcourse made up of approximately 21% oxygen is transferred from theadsorber into the storage chamber 69.

As the oxygen timer 184 has in the above manner provided for thepreselected amount of oxygen with this being retained in the adsorber 70for later use, the carbon dioxide timer now takes over to control theamount of carbon dioxide introduced into the storage chamber 69.

At the end of the preselected time, as set on the oxygen timer 184 inthe manner described above, the motor 186 of the oxygen timer pulsesswitch 198 (third switch) down to engage the bottom contact 223. Asswitch arm 193 is still in engagement with contact 197, this causescurrent to flow from line through line 212, switch 193, contact 197,line 213, switch 198, contact 223 and line 211 into solenoid coil 190(first energizable means) of the carbon dioxide timer 183. It alsocauses current to flow through motor 191 (second energizable means) ofthe carbondioxide timer by way of the motor circuit 209. The other sideof the current supply is provided by the line 157. This energizing ofsolenoid 190 moves switches 189 (second switch) and 202 (third switch)down to engage contacts 208 and 207, respectively. The energizing of thesolenoid 190 and motor 191 starts the operation of the carbon dioxidetimer 183. This de-energizes cycle timer motor since switch arm 202breaks contact with contact 206 and energizes valve motor 53 when switcharm 202 engages contact 207 to move valve damper 52 to the dotted lineposition so that this valve damper is moved along with those ofpreviously energized valve motors 59, 77 and 84 which are stillenergized. During this period the adsorber 71 is still being reactivatedwith air blown through it from blower 79, as described above.

The carbon dioxide timer 183 continues to operate by reason of themoving down of the switches 189 and 202, as described above. Immediatelywith the closing of these switches, switch 200 (second switch) of theoxygen timer 184 is momentarily opened by motor 186 (second energizablemeans) through its connection therewith, as indicated at 201, and thisbreaks the circuit to the holding solenoid (first energizable means)thereby permitting switches 193 and 188 of the oxygen timer 184 toreturn to their up position as shown in FIGURE 8. This results in valvemotor 67 then being energized by power supplied from line 170 by way ofline 212, switch arm 193, contact 195 and line 182 to the motor 67. Theenergizing of motor 67 moves valve damper 66 to its dotted line positionas 1 1 shown in FIGURE '1. With valve motors 59, 77, 84, 53 and 67 nowenergized, the carbon dioxide rich gases from the condenser 26 now flowthrough line 44, valve 45, line 50, valve 51 (fourth valve), line 62,valve 65 (third valve) and line 68 into the storage chamber 69.

During this period, as previously mentioned, timer motor 175 isde-energized as this supplying of the storage chamber with gases rich incarbon dioxide by-passes adsorber 70 which still contains the entrappedoxygen containing air, as previously described. This condition ofsupplying carbon dioxide rich gases directly to the storage chambercontinues for the preselected time set on the carbon dioxide timer 183to provide a predetermined amount of carbon dioxide in the chamber. Atthe end of the preselected time, interval switch 203 of the carbondioxide timer is pulsed open by timer motor 191 to open the circuit tothe solenoid holding coil 190. This stops the operation of the carbondioxide timer and it auto matically resets itself to zero in preparationfor later starting a new carbon dioxide portion of the cycle.

With the de-energizing of solenoid 190 switches 189 and 202 return totheir solid line positions, as shown in FIG- URE 8, with switch 202moving out of engagement with contact 207 and into engagement withcontact 206. This breaks the circuit to valve motor 53 so that now onlyvalve motors 59, 77, 84 and 67 are energized. At the same time the cycletimer motor 175 is energized by way of line 180, contact 206 and switch202 in the carbon dioxide timer 183, line 169, contact 150, pole 146 andline 143. With this arrangement the combustion gases now pass from thecondenser 26 through line 44, valve 45, line 50, valve 51, line 54, line55, valve 56, adsorber 70, valve 76, line 63, valve 65 and line 68 intothe storage chamber 69. The passage of these gases through the adsorber70 not only removes carbon dioxide from the gases, with the carbondioxide being adsorbed by the adsorber, but also carries the previouslypredetermined amount of oxygen that had been held all this time inadsorber 70 into the storage chamber 69 along with the above carbondioxide free gases.

The length of time that the gases are passed through the adsorber 70 inthis manner is controlled by the cycle timer 174. At the end of thepreset time on the cycle timer 174 the cam 176 moves the switch arm 177to the right, as shown in FIGURE 7, to disengage contact 178 and engagecontact 179.

The moving of the cycle timer arm 177 in the manner previously describedstarts a new cycle of operation by using adsorber 71 in this cycleinstead of adsorber 70.

The engaging of cycle timer arm 177 with contact 179 de-energizes valvemotors 59, 77 and 84 and energizes valve motors 61 and 89. Thisenergizing of motors 61 and 89 moves dampers 60 and 88, respectively, totheir dotted line positions. The de-energizing of motor 84 permitsdamper 83 to return to its solid line position and the dampers 58 and 76are similarly permitted to return to their dotted line position. Thismeans that air from the blower 79 now is directed by way of line 81,valve 82, line 78 and valve 77 down through the adsorber 70 and throughvalve 56 and line 74 into the exhaust line 49 which exhausts to ambientatmosphere. This air flow downwardly through the adsorber 70 serves toreactivate the adsorber by removing adsorbed carbon dioxide.

The de-energizing of valve motor 84, as previously described, and theresulting movement of the damper to its solid line position, as shown inFIGURE 1, again pulses air switch 85 for momentary contact of its arm222 with the contact 221 so that the whole cycle begins over again, aspreviously described, except now adsorber 71 is in the system toinitially receive gases from the condenser 26 while the adsorber 70 isbeing reactivated with air removing carbon dioxide therefrom asdescribed.

The carbon dioxide timer 183 and oxygen timer 184 are adjustable, aspreviously described, to provide the desired operating conditions. Inone embodiment the gases from the condenser were passed upwardly throughadsorber 70 (or 71) for approximately 0.8 minute to remove excess airand vent it to the ambient atmosphere and leave the desired amount ofoxygen in the selected one of the adsorbers for later use in the storagechamber 69. The carbon dioxide timer was set so as to allow the gasesrich in carbon dioxide from the condenser, at another period in theoperating cycle, to by-pass the adsorbers for approximately 2.7 minutesand pass directly to the storage chamber 69. The period of time in whichthe carbon dioxide free gases, as well as the remaining oxygen left inone of the adsorbers, were passed from the adsorber to the storagechamber 69 was approximately 5.2 minutes. The startup time during whichthe burner gases were vented to the ambient atmosphere by the by-passvalve 45 was about 15 minutes.

The catalytic combustion provided by the apparatus of this inventiontogether with cooling of the catalyst bed permits control of thetemperature of combustion within a practical range of about 12002000 F.Under these conditions the products ofcombustion have no measurableamounts of oxides of nitrogen.

In a preferred apparatus the air that is provided by the blower to theburner is preferably in about 5% excess over that required for completecombustion of the fuel.

In practical embodiments of the invention the percentage of oxygen inthe atmosphere supplied to the storage chamber is between 1 and 10% byvolume. In most instances, the amount of carbon dioxide in thisatmosphere is preferably between about 1 and 15% by volume.

The catalyst used in the burner of this apparatus is of the typepreviously described in Bedrosian et a]. Patent 3,102,778, also assignedto the same 'assignee as the present application. Thus, a typicalcatalyst is a chrome-alumina catalyst containing 20% chromic oxide inthe form of /s inch extruded pellets.

The amount of carbon dioxide supplied to the storage chamber 6'9 and theamount of oxygen supplied to the storage chamber are controlled by thetimers 183 and 184, as previously described. The interrelationship ofthe various variable controls is shown on the graph of FIGURE 9. Thisfigure illustrates conditions of a typical catalytic burner producingexhaust gases containing 0.8% oxygen and 12.5% carbon dioxide. Theabscissa of the graph gives the percentage of oxygen that is desired inthe storage chamber with the amounts varying from 0% to 6%. The ordinateof the graph gives the amount of carbon dioxide desired in the storagechamber between 0% and 12.5 The generally vertical slope lines marked0.0 to 1.00 progressing from the lower right-hand corner to the upperleft-hand corner of the graph are the purge times, giving the time inminutes during which burner gases are passed up through each adsorber inturn to purge the adsorber of the desired amount of air and to retainthe desired amount of air in order to provide the preselected quantityof oxygen in the storage chamber. The generally horizontally slopedlines marked at the right-hand side of the graph give the by-pass timein minutes during which the adsorber is by-passed and the carbon dioxiderich gases are passed directly into the storage chamber in the mannerpreviously described through valves 45, 51 and and interconnectingconduits 44, 50, 62, 63 and 68. As can be seen, this time varies fromzero to 20 minutes.

Thus, to provide an atmosphere in the storage chamber of 2% oxygen and4% carbon dioxide, the purge time during which the burner gases werepassed through the adsorber to remove excess oxygen therefrom would beabout 0.8 minute. The by-pass time during which carbon dioxide richgases from the burner Were passed directly into the chamber, by-passingthe adsorber, would be about 2.6 minutes. The other conditions forproducing other percentages of oxygen and carbon dioxide from the burnercan of course be easily determined from the graph of FIGURE 9.

Each adsorber not only removes carbon dioxide from The embodiment of theinvention in which an exclu- Y sive property or privilege is claimed isdefined as follows:

1. Apparatus for providing and maintaining an oxygen containingatmosphere in a receiver at a preselected level of oxygen content,comprising: means for generating a gas mixture comprising carbondioxide; a place of disposal; adsorption means for removing undesirableamounts of preselected constituents including said carbon dioxide fromsaid gas mixture; 21 source of air; means for directing said air throughsaid adsorption means to remove and dispose of said preselectedconstituents including carbon dioxide, at least a portion of said airbeing retained by said adsorption means; means for directing said gasmixture through said adsorption means to said place of disposal for afirst predetermined time period to remove a preselected portion of saidair retained in said adsorption means; and means for then directing saidgas mixture through said adsorption means to said receiver for a secondpredetermined time period to remove said constituents from said gasmixture, and to transfer the unremoved portion of said gas mixture andthe remaining quantity of said air retained in said adsorption meansfrom said adsorption means to said receiver.

2. The apparatus of claim 1 wherein there are provided means forperiodically by-passing said adsorption means with said gas mixture andflowing directly into said receiver for a third predetermined timeperiod to provide carbon dioxide rich atmosphere to said receiver.

3. The apparatus of claim 1 wherein said means for generating comprisesa combustion means for providing a gas mixture comprising said carbondioxide and oxygen, said source of air provides pressurized air, andthere are provided means for initially directing said mixture to saidplace of disposal prior to said directing of said mixture through saidadsorption means.

4. The apparatus of claim 3 wherein there are provided means forperiodically by-passing said adsorption means with said mixture andflowing directly to said receiver to provide carbon dioxide richatmosphere thereto.

5. The apparatus of claim 4 wherein said means for directing air throughsaid adsorption means, said means for directing said mixture throughsaid adsorption means to said place of disposal, and said means fordirecting said mixture through said adsorption means to said receivercomprises a cycle of operation thorugh said adsorption means, and thereare provided a second adsorption means, means for then repeating saidcycle through said second adsorption means while isolating said firstadsorption means from said gas mixture providing means and receiver, andmeans for directing air through said first adsorption means during saidisolating to remove carbon dioxide from said first adsorption means.

References Cited UNITED STATES PATENTS 8/1965 Brown et a1. 23-281 9/1965Lannert et al 23281 JOSEPH SCOVRONEK, Primary Examiner.

